Improvement in grinding-mills for ores



duidt tata JACOB S. NISWANDER, OF OAKLAND, CALIFORNIA.

Letters Patent No. 113,085, dated March 28, 18,71.

IMPROVEMENT IN GRlNDlNG-MILLS FOR ORE-S.

The Schedule referred to in these Letters Patent and making part of thelame.

To all whom it may concern Be it known that I, JAooB S. Nrswsnnnn, ofOakland, county of Alameda, State of California, have invented auImproved Grinding-Mill for Ores; and I do hereby declare the followingdescription and accompanying drawing are sulcient to enable any personskilled in the artor science to which it most nearly appertains to makeand use my said invention or improvements without further invention orexperiment.

My invention relates to improvements in the construction and operationof quartz-grinding mills, the object being to do away with'the necessityof employi'ng iron grinding surfaces, whereby the amalgamation andseparation ofthe metals are always more or less retarded by theparticles of iron which are detached and mingled with the pulp duringthe process of grindlng. l

My invention consists in so constructing the grinding-pan or structurethat ordinary stones or the quartz-rock of the mine, and selected with aview to obtain a medium lcv-el face or surface, can beemployed as abedorunder grinding surface.

The muller is constructed so that it can be filled with loose rock,which will bear and grind upon thc lower or under surface, and betweenwhich the broken or pulver-ized rock which is fed to the mill is ground.

In order to more fully explain my invention reference is had to theaccoim'ianyiug drawing forming a part of this specification, in which- Arepresents a horizontal iron disk, which is fixed upon a vertical shaft,15,01- otherwise arranged so that, if desired, it can be revolved in`oneor either direction.

This disk is provided with a narrow vertical rim or flange, c, aroundits upper periphery, thus forming it into a shallow pan.

Between thisI fla-nge cfaud the center conical disk (l I pack orplaceordinary pieces of rock of any character, taking care to give as levelan upper grinding surface as possible; or, if desired, the entiresurface of the pan can he covered with rock properly packed,- thus doingaway with the central cone. These rocks are 'placed as closely' togetheras possible and the interstices filled with broken stones, which arefirmly wedged in between the larger ones.

In order to keep this bed of stones in place one or more rings or bands,e, can be placed upon the flange c, so as to form a sideor rim to thepan or disk A, for the purpose of keeping the bed of stones in place..

These rings canv lie-made iu twoparts and hinged together at one' side,so as to be opened out when it is desired to remove them, and heldtogether on the opposite side by a screw 'or equivalent device, byvwhich they can he tightly drawn around the bed of stones.

The muller F consists of a circular rim or shell, which 'may or may notbe provided with a. cover, as most convenient.

This rim is divided into several compartments, m, by partitions, g, asshown. In each of these compartments I place loosely large stones, suchas are readily picked up about any mine. By then giving either the rim Aor muller F a rotary motion the surface of one will grind upon thesurface of the other and soon wear an excellent grinding surface.

The pulp or pulverized ore is then introduced through the center of themullcr to the grinding surrocks, as required, and by this means it ispossible to 'Y keep an even grinding surface at alltimes, thus insnringa better grinding of the ore fed to the mill.

\Vhen the lower grinding surface has'become wornv 'down to the upperring this ring is removed, and the process continued until the undergrinding surface has been completely worn away, when it can berenewed,as above described. y

By this means I provide a grinding surface which will be quiteeifective, the sharp edges of the rocks serving to grind the pulverizedore to the required tineness. v

The vmill can be built at a small cost, and cannot get out of repair.

.I also accomplish the ,grinding of orcs without in` termingling withthe pulp finely-divided iron, which always, more or less, becomes mixedwith it when iron shoes and dies are used for grinding, and which is a.great drawback to the proper amalgamation of the metals.

Having thus described my invention, \Vhat I claim, and desire to secureby Letters Patent., isl l v 1. The rings or bands e, in combination withthe disk A, with its flange c, anda filling or bed composed of rock,substantially as and for the purpose set forth. 2. The muller I1', withthe openings m', and divided into two or more compartments, m, which arepartially filled with loose rock, substantially as and t'or the pnr- 4Witnesses WM.- H. RUNNnLs, Gao. H. STRONG.

